Genetic Variant KRT33B:p.Arg393Cys (chr17-41363874-G-A) – ACMG Classification: Likely_benign (-6 pts)

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_ModerateBS2

The NM_002279.5(KRT33B):c.1177C>T(p.Arg393Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000931 in 1,611,452 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R393H) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000089 ( 2 hom. )

Consequence

KRT33B
NM_002279.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.94

Variant links:

Genes affected

KRT33B (HGNC:6451): (keratin 33B) This gene encodes a member of the keratin gene family. This gene is one of multiple type I hair keratin genes that are clustered in a region of chromosome 17q12-q21 and have the same direction of transcription. As a type I hair keratin, the encoded protein is an acidic protein which heterodimerizes with type II keratins to form hair and nails. There are two isoforms of this protein, encoded by two separate genes, keratin 33A and keratin 33B. [provided by RefSeq, May 2012]

KRT33B links:

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ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -6 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.19912288).

BS2

High Homozygotes in GnomAdExome4 at 2 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KRT33B	NM_002279.5 link	c.1177C>T	p.Arg393Cys	missense_variant	Exon 7 of 7	ENST00000251646.8	NP_002270.1	Q14525

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KRT33B	ENST00000251646.8 link	c.1177C>T	p.Arg393Cys	missense_variant	Exon 7 of 7	1	NM_002279.5	ENSP00000251646.3		Q14525

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

151130

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000247

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000120

AC:

AN:

250432

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135376

show subpopulations

Gnomad AFR exome

AF:

0.000187

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000890

AC:

AN:

1460322

Hom.:

Cov.:

AF XY:

0.00000551

AC XY:

AN XY:

726418

show subpopulations

Gnomad4 AFR exome

AF:

0.000211

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000116

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000450

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000132

AC:

AN:

151130

Hom.:

Cov.:

AF XY:

0.0000271

AC XY:

AN XY:

73810

show subpopulations

Gnomad4 AFR

AF:

0.0000247

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000117

Hom.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Oct 29, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1177C>T (p.R393C) alteration is located in exon 7 (coding exon 7) of the KRT33B gene. This alteration results from a C to T substitution at nucleotide position 1177, causing the arginine (R) at amino acid position 393 to be replaced by a cysteine (C). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Benign

-0.20

BayesDel_noAF

Benign

-0.24

CADD

Benign

DANN

Benign

0.83

DEOGEN2

Benign

0.0013

Eigen

Benign

-0.66

Eigen_PC

Benign

-0.66

FATHMM_MKL

Benign

0.080

M_CAP

Benign

0.011

MetaRNN

Benign

0.20

MetaSVM

Benign

-0.62

MutationAssessor

Benign

1.4

PrimateAI

Benign

0.43

PROVEAN

Benign

0.92

REVEL

Benign

0.21

Sift

Benign

0.055

Sift4G

Benign

0.095

Polyphen

0.0010

Vest4

0.52

MutPred

0.34

Gain of catalytic residue at P392 (P = 0.009);

MVP

0.37

MPC

0.45

ClinPred

0.095

GERP RS

3.9

Varity_R

0.060

gMVP

0.36

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over